Centrifugal compressor



Fig.2..

D. R. HouLTs 2,373,713

CENTRIFUGAL COMPRES SOR April 17, 1945.

Filed May 20, 1942 2 Sheets-Sheet l 0 4 W O O J L 0 Inventor;

David R. Shoults by His AttoTr'wey.

April 17, 1945. D, R. SHOULTS CENTRIFUGAL COMPRESSOR I Filed May 20, '1942 2 Sheets-Sheet 2 Fig-4.

Inventor; David F3. Sh'outs,

Patented Apr. 17, 1945 "UNITED STATES. oFF cr.

David a. Shoults', Schenectady, N. Y., assignor to.

General Electric Company, acorporation .of

New York Application May 20, 1942, Serial N 0. 443,747

2 Claims. c1. 230-209) The present invention relatesto centrifugal compressors and especially to centrifugal compressors such as are used on aircraft to provide air at aidesired pressure for supercharging an aircraft engine," a cabin, or the like. I

In the operation with such compressors the air is heated to'a considerable extent by the action of the compressor, making it desirable in many instances to provide a cooler or heat exchanger the compressor to the point of consumption.

The object of my invention is to provide an im- I proved construction and arrangement wherein the cooler or heat exchanger is built directly into the compressor, forming in substance a unitary part thereof, and for a consideration of whatr believe to be novel and my invention attention is directed to the following specification and to the claims appended thereto.

In the drawings, Fig. 1 is a face view, with parts broken away, of a structure embodying my invention; Fig. 2 is a sectional view taken on'line 22, Fig. 1; Fig. 3 is a detail view showing the structure mounted on an aircraft; Fig. 4 is a detail view of a modification; and Fig. 5 is a perspective view of a part of a cooler shown in Fig. 4.

Referring to the drawings, I indicates a shaft carried in a suitable bearing 2 and having mounted thereon an impeller 3 of known construction.

The eye or inlet of the impeller is indicated at 4 and the impeller blades are indicated at 5. The compressor casing is indicated at 6 and the discharge scroll at 1. Shaft. I maybe driven by any suitable means. In the case of an aircraft supercharger, for example, it may be driven by a turbine wheel operated by exhaust gases from an aircraft internal combustion engine.

Located between the discharge ends of the impeller vanes and the discharge scroll I is a diffuser having vanes which define passages for converting velocity of the medium being compressed into pressure, and according to my invention I provide a diffuser which functions also as a cooler .or

heat exchanger to effect cooling of the medium being compressed as it passes through the diffuser. Tothis end, I provide the diffuser with hollow vanes through which cooling medium flows, and in addition to the usual or what may be termed the primary set of vanes, I provide preferably anadditional set or sets of hollow vane interspersed with the'primary set, each additional interspersed set being shorter in a radial direction than the preceding set. In addition, I may provide, if found desirable, an annular cooler or heat exchange unit which surrounds directly the diffuser and is in series therewith as regardsthe flow" of medium to be cooled and in parallel therewith as regards: the flow of cooling medium.

Ihe primary set of cQol-ingyanes isindicated at 8. 'These vanes define curved diffuser passages 9 shaped to convert velocity of medium flowing through them into pressure. Interspersed between vanes. B are a plurality of sets of hollow vanes III, II and I2, the sets being successively shorter as shown clearly in Fig. 1. sets of vanes are supported on one side in suitable openings in casing wall I3 and on the other side in openings in an annular side plate I4 fixed in and forming apart of the other side wall of the casing. In the present instance, I have shown three additional sets of vanes arranged between the vanes 8. However, more than this number may be used, the arrangement being such preferably that at the radially outer portion of the diffuser the vanes are quite close together so that all the air comes into intimate contact with a cooling surface to multiply the cooling effect. By correctly shaping the passages between the vanes and by gradually increasing the number of vanes from the radially inner end of the diffuser to the radially outer end, the functioning of the diffuser as a device for converting velocity into pressure is not adversely affected and at the same time it is made to function efliciently as a cooler or heat exchanger.

Medium to be compressed and cooling medium may be conveyed to the impeller inlet and to the cooler respectively by suitable conduits. In the case of an aircraft supercharger where the medium to be compressed and the cooling medium is air I may provide a single conduit I5 for both. Conduit I5 may be connected with a suitable ram I6 facing into the slip stream of the aircraft II,

as shown in'Fig. 3. This serves to set up a-positive pressure for effecting fiow of air through the cooler passages and to the eye of the impeller. Cooling air flowing through the cooler passages may discharge directly to atmosphere or to other suitable point.

The several exchanger I9 which directly surrounds the diffuser and is located in the discharge scroll. Such an arrangement is shown in Figs. 4 and 5 wherein spaced plates 20 define passages 2| for the cool ing medium and passages 22 for the medium to be cooled. Plates 2!] are held in spaced relation by spacers 23, the plates and pacers being suitably joined together by suitable means such as by brazing or the like or by being made integral with each other. The tructure is supported in the side walls of the discharged scroll 24. The difiuser is indicated at 25, the impeller at 26, and the' air supply conduit, at 21. They may be the same in structure and arrangement as are the corresponding parts of Figs. 1 and 2.

My invention has the advantages that it is relatively simple in structure, compact and light in weight; the two latter are especially important in the case of an aircraft supercharger since space and weight are important factorsin aircraft design.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention, together with the apparatus which I noW consider to represent the best embodiment thereof, but I desire to have it understood that the apparatus shown is only illustrative and that the invention may be carried out by other means.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A centrifugal air compressor for use on an aircraft comprising a bearing, a shaft in the bearing, an impeller on said shaft, a casing for the impeller comprising a wall which defines an axially facing inlet through which air is supplied to the impeller, a diffuser surrounding the im peller comprising axially extending curved vanes,

said vanes being hollow for flow of cooling air through them, a wall which surrounds said firstnamed wall in spaced relation thereto to define an annular passage for directing cooling air to said hollow vanes, and a conduit for directing air to said inlet and said annular passage.

2. A centrifugal air compressor for use on an aircraft comprising a, bearing, a shaft in the bearing, an impeller on said shaft, a casing for the impeller comprising a wall which defines an axially facing inlet through which air is supplied to the impeller, a diffuser surrounding the impeller comprising a plurality of sets of interspersed vanes, successive sets being shorter in radial extent, and said vanes being hollow for flow of cooling air through them, a wall which surrounds said first-named wall inspaced relation thereto to define an annular passage for directing cooling air to said hollow vanes, and a conduit for directing air to said inlet-and said annular passage.

DAVID R. SHOULTS. 

